Sterile suspensions, i.e. formulations containing at least two phases, a solid and a liquid phase, are difficult to manufacture in large scale. Suspensions are by definition thermodynamically unstable, and separation of the different phases will occur with time. Steam sterilization of such formulations often speeds up the separation. Aseptic preparation by filtration through a 0.2 .mu.m filter is not applicable on suspensions. There are few suspension products on the market of this type. Novalucol.RTM. and Roxiam.RTM. are examples of mixtures for oral administration. Oil containing suspensions for injection are available for CNS indications. There is a need for an injectable suspension which can be sterilized either by steam sterilization or by filtration through a 0.2 .mu.m filter.